ML20207M948
| ML20207M948 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/11/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20207M945 | List: |
| References | |
| NUDOCS 9903190299 | |
| Download: ML20207M948 (3) | |
Text
. _.
8*Ecg
.N d
UNITED STATES iy "\\ )fL E
NUCLEAR REGULATORY COMMISSION
- d ; .
_ E WASHINGTON, D.C. 20555-0001 ej
- * * *
- SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.1 MTO FACILITY OPERATING LICENSE NO. DPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271
1.0 INTRODUCTION
The Vermont Yankee Nuclear Power Station is a boiling water reactor (BWR), model BWR-4, with a Mark I containment. By letter dated April 23,1998, as supplemented on January 25, 1999, the Vermont Yankee Nuclear Power Corporation, the licensee for the Vermont Yankee Nuclear Power Station, submitted for Nuclear Regulatory Commission (NRC) staff review a proposed change to the Technical Specifications (TSs). The licensee requested an amendment to change the existing requirements in TSs 4.5.C and 3/4.5.D for the Station Service Water (SSW), the Residual Heat Removal Service Water (RHRSW), and the Alternate Cooling Tower Systems (ACS). The changes include replacing the allowance for continued operation with two inoperable SSW subsystems with a more conservative requirement to shut down the unit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, relocating certain SSW and RHRSW testing details to the Technical Requirements Manual (TRM), and revising the wording in the SSW TSs to more a' r:urately reflect the Vermont Yankee design and operation. Also, the Bases for the SSW and ACS Systems would be revised to omit statements that imply that the ACS could provide adequate heat removal following a postulated accident. The January 25,1999, supplement affirmed that the information had been duplicated in the TRM and the TRM had been incorporated by reference into the Final Safety Ar.alysis Report (FSAR). The January 25,1999, supplement did not affect the conclusions of the original proposed no significant hazards consideration determination.
2.0 BACKGROUND
The SSW system at the Vermont Yankee Nuclear Power Station is designed to provide water for turbine and reactor auxiliary equipment cooling during normal operation and to provide cooling water in conjunction with the RHRSW pumps for reactor shutdown cooling. Also, the SSW system provides cooling water to systems and equipment required to operate under accident conditions. The SSW system consists of a dual header system with two SSW pumps on each neader. Each header supplies cooling water to a reactor building closed cooling water system heat exchanger, emergency core cooling system room ventilation coolers, a diesel generator cooler, and a set of RHRSW pumps, which supply water to the RHR heat exchangers.
The RHRSW system is designed to provide a source of cooling water for the RHR system during norms! shutdown conditions and for the RHR system during a loss of off-site power. The RHRSW pumps are supplied from the SSW system, and the cooling water is then pumped through the RHR heat exchangers and is retumed to the SSW system.
9903190299 990311 PDR ADOCK 05000271 P
ATTACHMENT TO LICENSE AMENDMENT NO 169 FACILITY OPERATING LICENSE NC. DPR-28 DOCKET NO. 50-271 Replace the following pages of Appendix A Technical Specifications with the attached pages.
These revised pages are identified by amendment number and contain a vertical line indicating the area of change.
Remove Insert 103 103 104 104 105 105 111 111 111a
...- -..... ~.
..-.-..-........ -. ~ -. -...
I VYNPS 3.5 LIMITING CONDITION FOR 4.5 SURVEILLANCE REQUIREMENT OPERATION C.
C.
Residual Heat Removal (RHR) t Service Water System Service Water System l
Surveillance of the RHR Service Water System shall be performed as follows:
1.
Except as specified in 1.
RHR Service Water Specifications 3.5.C.2, subsystem testing:
and 3.5.C.3 below, both RHR Service Water Operability testing of J
Subsystem loops shall be pumps and valves shall operable whenever be in accordance with irradiated fuel is in Specification 4.6.E.
l the reactor vessel and j
prior to reactor startup from a cold condition.
2.
From and after the date 2.
When one of the RER that one of the RHR service water pumps is service water pumps is made or found to be made or found to be inoperable, the operable inoperable for any RHR service water pumps reason, reactor shall have been or shall operation is permissible be demonstrated to be only during the operable within succeeding thirty days 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
unless such pump is sooner made operable, provided that during such thirty days all other active components of the RHR Service Water Subsystem are operable.
3.
From and after the date 3.
When one RHR Service that one RHR Service Water Subsystem is made Water Subsystem is made or found to be or found to be inoperable, the active inoperable for any components of the i
reason, reactor redundant RHR Service operation is permissible teter Subsystem shall only during the nave been or shall be succeeding seven days demonstrated to be unless such subsystem is operable within sooner made operable, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
provided that all tetive components of the other RHR Service Water Amendment No. H4, He,16 9 103 R.
.. ~
~. -...
~
VYWPS 3.5 LI_MITING CONDITION FOR 4.5 SURVEILLANCE REQUIREMENT l
OPERATION Subsystem, both Core Spray Subsystems, and both diesel generators
{
required for operation of such components if no external source of power were available, shall be operable.
4.
If the requirements of Specification 3.5.C j
cannot be met, an orderly shutdown shall
)
be initiated and the reactor shall be in a cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
D.
Station Service Water and D.
Station Service Water and Alternate Cooline Tower Alternate Coolina Tower Systems system _s Surveillance of the Station Service Water and Alternate Cooling Tower Systems shall be performed as follows:
1.
Except as specified in Specifications 3.5.D.2 1.
Operability testing of and 3.5.D.3, the Station pumps and valves shall Service Water System and be in accordance with both essential equipment Specification 4.6.E.
cooling loops and the alternate cooling tower shall be operable whenever irradiated fuel is in the reactor vessel and reactor coolant temperature is greater than 2120F.
2.
From and after the date 2.
When the Station Service l that the Station Service Water System is made or Water System is made or found to be unable to' found to be unable to provide adequate cooling provide adequate cooling to one of the two to one of the two essential equipment essential equipment cooling loops, the cooling loops, reactor remaining active operation is permissible components of the only during the Station Service Water succeeding 15 days System, both essential unless adequate cooling equipment cooling loops, capability to both and the alternate essential equipment cooling tower fan, shall cooling loops is have been or shall be restored sooner, demonstrated to be provided that during operable within such 15 days all other 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
active components of the remaining essential equipment cooling loop and the Station Service Water and Alternate Cooling Tower Systems are operable.
Amendment No. 444, 4G4,16 9 104
VYNPS s
3.5 LIMITING CONDITION FOR 4.5 SURVEILLANCE REQUIREMENT l
OPERATION 3.
When the Alternate J
l 3.
From and after the date Cooling Tower System is i
l that the Alternate made or found to be l
Cooling Tower System is inoperable, all active made or found to be components of the Station i
?
inoperable for any Service Water System and reason, reactor operation both essential equipment is permissible only cooling loops shall have during the succeeding been or shall be j
j seven days, unless the demonstrated to be Alternate Cooling Tower operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
System is made operable, provided that during such j
seven days all active components of the Station Service Water System and both essential equipment cooling loops are i
4.
If the requirements of Specification 3.5.D 3
cannot be met, an orderly shutdown shall be 4
initiated and the reactor I
shall be in a cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
E.
High Pressure Cooling E.
High_,oressure Coolant Injection (HPCI) System Injectiba (HPCI) System Surveillance of HPCI System shall be performed as follows:
1.
Except as specified in j
Specification 3.5.E.2, 1.
Testinq l
whenever irradiated fuel is in the reactor vessel Item Frequency and reactor pressure is greater than 150 psig and Simulated Each re-prior to reactor startup Automatic fueling from a cold condition:
Actuation outage Test a.
The HPCI System shall be operable.
Operability testing of the pump and valves shall b.
The condensate be in accordance with storage tank shall Specification 4.6.E.
The contain at least HPCI System shall deliver J
75,000 gallons of at least 4250 gpm at condensate water, normal reactor operating pressure when recirculating to the Condensate Storage Tank.
Amendment No. M, M4, us, M4,16 9 105
7 VYNPS i
BASES:
3.5 (Cont'd)
D.
Station Service Water and Alternate Cooling Tower Systems The Station Service Water System consists of pumps, valves and associated piping necessary to supply water to two essential equipment cooling loops and additional essential and nonessential equipment cooling loads. Each of the two Station Service Water essential equipment cooling loops includes valves, piping and associated instrumentation necessary to provide e flowpath to essential equipment.
The Station Service Water essential equipment cooling loops provide redundant heat sinks to dissipate residual heat after a shutdown or accident.
Each Station Service Water essential equipment cooling loop provides sufficient heat sink capacity to perform the required heat dissipation.
Analyses have shown that any two service water pumps are capable of providing adequate cooling capability to the essential equipment cooling loops. To ensure this capability, four Service Water pumps and two Service Water essential equipment cooling loops must be operable. This ensures that at least two operable Service Water Pumps and one operable essential equipment cooling loop will be available in the event of the worst single active failure occurring coincident with a loss of off-site power. A Service Water pump is considered operable when it is capable of taking suction from an intake bay and transferring water to a Service Water essential equipment cooling loop at the specified pressures and flow rates.
An essential equipment cooling loop is considered operable when it has a flow path capable of transferring water to the essential equipment, when required.
The Alternate Cooling Tower System will provide the necessary heat sink for normal post-shutdown conditions in the event that the Station Service Water System becomes incapacitated due to a loss of t.he Vernon Dam with subsequent loss of the Vernon Pond, flooding of the Service Water intake structure (due to probable maximum flood in the river or an upstream dam failure) or fire in the service Water intake structure which disables all four Service Water pumps.
If one or more Station Service Water component (s) are inoperable such that the Station Service Water System would not be capable of performing its safety function, assuming a single active failure (e.g.,
a pump, valve or diesel generator), then at least one essential equipment cooling loop is inoperable.
If one or more component (s) are inoperable such that the Station Service Water System would not be capable of performing its safety function, even without assuming a single active failure, then both essential equipment cooling loops arc inoperable.
i Although the Station Service Water (SSW) System can perform its safety function with only two operable SSW pumps, the SSW System may not be j
capable of p3rforming its safety function assuming one or two inoperable SSW pumps and assuming a worst case single active failure (e.g.,
failure of a diesel generator, SSW pump, SSW valve, etc.).
Therefore, reactor
{
operation with one or two inoperable SSW pumps is limited to 15 days provided that during this time both the normal and emergency power supplies for the remaining operable SSW pumps are also operable, in addition to demonstra*.ing the operability of all remaining active components of the SSW system which perform a safety function and the alternate cooling tower fan.
If the SSW System would not be capable of performing its safety function for a reason other than one or two SSW pumps being inoperable, assuming a worst case single active failure (e.g.,
failure of a diesel generator, Amendment No. 34, 4++,169 111
VYNPS BASES:
3.5 (Cont'd)
SSW pump, SSW valve, etc.), then reactar operation is limited to 15 days provided that during this time both the normal and emergency power supplies for the remaining operable equipment are also operable, in addition to demonstrating the operability of all remaining active components of the SSW system which perform a safety function and the alternate cooling tower fan.
If the SSW System would not be capable of performing its safety function for any reason, even without assuming a worst case single active failure, then the reactor must be placed in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
E.
High Pressure Coolant Iniection System The High Pressure Coolant Injection System (HPCIs) is provided to adequately cool the core for all pipe breaks smaller than those for which the LPCI or Core Spray Cooling Subsystems can protect the core.
The HPCIs meets this requirement without the use of outside power.
For the pipe breaks for which the HPCIs is intended to function the core never uncovers and is continuously cooled; thus, no clad damage occurs and clad temperatures remain near normal throughout the transient.
Reference:
Subsection 6.5.2.2 of the FSAR.
F.
Automatic Depressurization System The relief valves of the Automatic Depressurization System are a backup to the HPCIs.
They enable the Core Spray Cooling System or LPCI Subsystem to provide protection against the small pipe break in the event of HPCI failure by depressurizing the reat 7r vessel rapidly enough to actuate the Core Sprays or LPCI Subsystem. Either of the two Core Spray Cooling Systems or LPCIs provides sufficient flow of coolant to prevent clad melting. All four relief valves are included in the Automatic Pressure Relief System.
(See VYNPS, FSAR Vol. 4, Appendix B.)
G.
Reactor Core Isolation Cooling System The Reactor Core Isolation Cooling System (RCIC) is provided to maintain the water inventory of the reactor vessel in the event of a main steam line isolation and complete loss of outside power without the use of the emergency core cooling systems.
The RCIC meets this requirement.
Reference Section 14.5.4.4 FSAR.
The HPCIS provides an incidental backup to the RCIC system such that in the event the RCIC should be inoperable no loss of function would occur if the HPCIS is operable.
H.
Minimum Core and Containment Cooling System Availability The core cooling and the containment cooling subsystems provide a method of transferring the residual heat following a shutdown or accident to a heat sink.
Based on analyses, this specification assures that adequate cooling capacity is available by precluding any combination of inoperable components from fulfilling the core and containment cooling function.
It is permissible, based upon the low heat load and other methods available to remove the residual heat, to disable all core and containment cooling systems for maintenance if the reactor is cold and shutdown and there is no potential for draining the reactor vessel.
However, if refueling operations are in progress, one coolant injection system, one diesel and a residual of at least 300,000 gallons is required to assure core flooding capability.
Amendment No. G4, 444,169 lila
. The ACS is designed to provide the necessary heat sink for normal post-shutdown conditions in the event that the SSW becomes incapacitated due to a loss of the Vernon Dam with a i
subsequent loss of the Vernon Pond, flooding of the SSW intake structure or a fire in the SSW intake structure, which disables all four SSW pumps.
FSAR Section 10.8.2 states that the ACS is not classified as an Engineered Safeguard System and is not designed to accept the consequences of a design basis loss-of-coclant accident.
The licensee discovered that the Bases for the SSW system TS contradicted the FSAR by incorrectly assuming that the ACS was capable of removing post-accident heat loads.
Regulatory guidance in SECY 97-035 dated February 1,1997, states in part, that upon discovering that the TSs are not consistent with the respective safety analysis, the licensee should take the appropriate action to put the plant in a safe condition (such as imposing more conservative administrative limits) and also take action (such as requesting a license amendrnent) so the TS represents the minimum requirements. As a result, the licensee implemented administrative controls to require a shutdown if both SSW subsystems are made or found to be inoperable. Additionally, the licensee submitted the license amendment as discussed below.
3.0 EVALUATION Currently, TS 3.5.D.3 includes an allowance for 7 days of operation after both SSW subsystems are made or found to be inoperable. This allowance was incorrectly based on the assumption that the ACS is able to fulfill the post-accident heat removal requirements when both SSW subsystems are made or found to be inoperable. However, the licensee stated that since the ACS is designed to be aligned and operated in a controlled manner, which takes approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, it is not designed to accept the consequences of a design basis loss-of-coolant accident. Therefore, the licensee has proposed to remove the existing allowance for 7 days of operation with both SSW subsystems inoperable in TS 3.5.D.3 and TS Surveillance 4.5.D.3, and replace it with a requirement to shut down the unit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The staff finds this change to be acceptable since it removes the allowance to operate in excess of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with both SSW subsystems inoperable.
The remaining portion of TS 3.5.D.3 allows for continued operation for 7 days with an inoperable ACS and is not affected by this change. The low probability of either a dam failure, a fire in the SSW pump room, or flooding in the SSW pump room, which would require the use of the ACS for shutdown of the unit, provides the basis for this allowed outage time. Since this basis is not affected, there are no changes nccessary to the ACS requirements.
In proposed TS 4.5.C.1 and TS 4.5.D.1, the licensee has relocated the testing details for the RHRSW and SSW systems to the Technical Requirements Manual (TRM). Any changes to these relocated requirements in the TRM would be controlled by 10 CFR 50.59 since the TRM will be incorporated into the FSAR by reference. The staff finds this change to be acceptable since these details are not required by 10 CFR 50.36 to be contained in the TSs and control of these changes in accordance with 10 CFR 50.59 is adequate. This change is also in conformance with NUREG-1433, Revision 1, " Improved Standard Technical Specifications."
In proposed TSs 3.5.D.1,3.5.D.2,3.5.D.3,4.5.D.2,4.5.D.?, and the associated Bases, the licensee has replaced the word " subsystem" with "essentir,1 equipment cooling loop." The SSW
1
~.
. system at Vermont Yankee consists of four SSW pumps, associated valves and piping, one nonessential equipment cooling loop, and two essential equipment cooling loops and additional essential and nonessential equipment cooling loads. The essential equipment cooling loops provide redundant capability for analyzed accidents or transients. Two operable SSW pumps with one or both essential equipment cooling loops in operation will provide adequate cooling for analyzed accidents or transients. The staff finds this change to be acceptable since the licensee's proposed change to " essential equipment cooling loop" would more accurately reflect the Vermont Yankee design and operation.
In the Bases for TS 3.5.D, the licensee has removed the statements that imply that the ACS could provide adequate heat removal following a postulated accident and replaced them with a discussion on the actual capabilities of the ACS. The staff has no objection to the proposed Bcses change.
Based on its review, the staff concludes that the licensee's proposed TS changes to replace the allowance for continued operation with two inoperable SSW subsystems with a more conservative requirement to shut down the unit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, to relocate certain SSW and RHRSW testing details to the TRM, and to replace the references to SSW " subsystem" with
" essential equipment cooling loop" to more accurately reflect the Vermont Yankee design, are acceptable for the reasons previously stated.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Vermont State official was notified of the proposed issuance of the amendment. The State official had no comments.
I
5.0 ENVIRONMENTAL CONSIDERATION
j The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types of any effluents that may be celeased offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such 'inding (64 FR 6713). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in tM proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Vonna Ordaz Date: March 11, 1999
.